Ballooning Stability of Separatrix Spanning Modes
Abstract
The ideal ballooning stability of the near-separatrix tokamak plasma and its possible relation to the Greenwald density limit, as discussed in, motivates the present work. We consider a sequence of CORSICA-generated equilibrium shapes with varying elongation and examine the marginal stability of infinite-n and finite-n separatrix-spanning modes using the 2DX and ArbiTER eigenvalue codes. The elongation scaling of the result provides a test of the proposed density-limit theory. A new computationally efficient technique for dealing with the phase variation of moderate-n modes across the branch cut in field-line following coordinates will also be discussed.
Work supported by US DOE grants DE-FG02-97ER54392 and DE-SC0006562.- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- October 2013
- Bibcode:
- 2013APS..DPPPP8038M